Universal snow plow adapter

ABSTRACT

The present invention provides an apparatus and method for allowing the use of a common lift assembly with both trip edge snow plow blades and full moldboard trip snow plow blades. A bracket is interposed between a lift assembly, which is adapted to attach directly to a trip edge blade, and a full moldboard trip blade. This bracket is pivotally attached to the lift assembly, so as to allow it to pivot about a vertical axis. It is also pivotally attached to the full moldboard trip blade so as to allow the blade to pivot about a horizontal axis. This allows a single lift assembly to be used in conjunction with both trip edge blades and full moldboard trip blades.

BACKGROUND OF THE INVENTION

Snow plows are commonly used in conjunction with general purpose vehicles, such as trucks, to clear roads, driveways and other paths. However, these roads and paths are not always flat and free of obstacles. Because of the possibility of a plow encountering an immovable object, such as a curb, precautions are typically incorporated into the plow system. There are two common implementations used to protect the snow plow system from such obstacles.

One such implementation incorporates a “trip edge” into the snow blade. In this embodiment, the “trip edge” is typically hinged at the lower edge of the plow blade. This edge is typically about nine inches tall and is hinged so as to allow it to move backward when encountering an immovable object. Typically, the trip edge is held in position through the use of biasing elements, such as springs. In operation, the springs hold the trip edge in place as the plow blade is used. When an immovable object, such as a curb, is encountered, the force created by the trip edge against the immovable object will exceed the force exerted by the springs, thereby allowing the trip edge to pivot away from the object. Once the object has been passed, the force of the springs again returns the trip edge to its operative position.

A second such implementation allows the entire plow blade, or moldboard, to pivot when it encounters an immovable object. In this embodiment, the entire moldboard is hinged to the accompanying frame and lift system, thereby allowing it to pivot about a horizontal axis.

Each of these configurations has its perceived advantages and disadvantages. Similarly, each configuration has strong advocates among those who buy snow plows. Because both versions are popular with consumers, and neither is clearly preferred over the other, many manufacturers and dealers design, manufacture and sell both types of systems.

While this allows consumers the opportunity to choose between the two implementations, there are serious disadvantages to the dealers and manufacturers. Manufacturers are forced to develop two separate snow blades and two separate lift assemblies. Similarly, dealers are forced to order and stock both types of systems, as well as spare parts for each.

Therefore, it would be advantageous to develop an apparatus and a method whereby the number of different components used in these two implementations is minimized. This would reduce design and manufacturing costs from the manufacturers and would reduce inventory and carrying costs for the dealers.

SUMMARY

The problems of the prior art are overcome by the present invention which provides an apparatus and method allowing the use of a common lift assembly with both trip edge blades and full moldboard trip blades. A bracket is interposed between a lift assembly, which is adapted to attach directly to a trip edge blade, and a full moldboard trip blade. This bracket is pivotally attached to the lift assembly, so as to allow it to pivot about a vertical axis. It is also pivotally attached to the full moldboard trip blade so as to allow the blade to pivot about a horizontal axis. This allows a single lift assembly to be used in conjunction with both trip edge blades and full moldboard trip blades.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective drawing of a lift assembly for a full moldboard trip blade of the prior art;

FIG. 2 is a side view of a full moldboard trip blade showing the tilting operation of the blade;

FIG. 3 is a perspective drawing of a lift assembly, as it is attached to a trip edge blade;

FIG. 4 is a perspective drawing of the lift assembly of FIG. 3, as attached to a full moldboard trip blade in accordance with the present invention; and

FIG. 5 is a perspective drawing of the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a lift assembly 10 for use with a full moldboard trip blade (not shown). The snow plow blade pivotally attaches to points 20 a,20 b,20 c and 20 d on arm 95. These points 20 provide a hinge about which the plow blade can pivot. To maintain the snow plow blade in its operative position, biasing elements, preferably springs 80, are used to exert force on the top edge of the plow blade.

FIG. 2 shows the tilting operation of the full moldboard trip blade. One or more biasing elements 80 is used to hold the top of the blade 200 in the operative position. When a strong force, or immovable object exerts pressure on the bottom edge of the blade, the blade pivots at point 20. In order to start pivoting, the force exerted at the bottom of the blade must exceed that exerted by the biasing element(s) at the top edge of the blade. If the force is greater, the blade will pivot about point 20. As it pivots, the biasing elements are stretched, thereby increasing the backward force that they are exerting on the top edge of the blade 200. When the force (or object) is no longer present, the biasing elements force the blade 200 back to its operative position.

FIG. 1 also shows two actuators 70 a, 70 b, such as hydraulic cylinders, which are used to pivot arm 95 about a pivot point 90. When the right actuator 70 a is expanded and the left actuator 70 b is contracted, the arm 95 pivots in a counterclockwise direction about pivot point 90. Arm 95 is also in communication with arc 89 and bracket 88, to which the biasing elements 80 are affixed. Therefore, arm 95, arc 89, bracket 88, biasing elements 80 and the plow blade move in unison in response to relative movement of actuators 70 a, 70 b. This integral motion is imperative to the operation of a full moldboard trip blade.

Other implementations of lift assemblies for full moldboard trip blades are well known to those skilled in the art, and are widely used. While these other implementations can differ in various respects, there are several common characteristics among them. First, the biasing elements 80 moves in unison with the movement of the blade in order to operate properly when the blade is turned. Second, the cylinders 70 do not attach directly to the blade, because of the need for the blade to freely pivot about a horizontal axis. Third, the pivot point 90 about which the blade vertically rotates typically is not integral with the blade, because of the need for the blade to freely pivot about a horizontal axis.

FIG. 3 shows a perspective drawing of a trip edge snow plow blade 300, mated with a lift assembly 310. The trip edge 301 is pivotally attached to blade 300 at attachment points 302. Force from biasing elements 303 a, 303 b, 303 c, and 303 d holds the trip edge 301 in its operative position. When an external force or immovable object exerts pressure against the front side of trip edge 301, the trip edge rotates about the horizontal axis defined by attachment points 302. This rotation forces rod 304 to move in an upward direction, thereby causing biasing elements 303 to expand. This expansion creates a downward force on rod 304, such that the trip edge 301 returns to its operative position as soon as the immovable object is no longer present, or the external force is less than the force exerted by the biasing elements 303. Although four biasing elements are shown, those skilled in the art will appreciate that fewer or more could be used without departing from the scope of the present invention.

Blade 300 is not required to pivot about any horizontal axes, since the trip edge 301 is able to perform this rotation in the presence of excessive force or immovable objects, such as curbs. Consequently, lift assembly 310 is pivotally attached directly to blade 300 at vertical pivot location 311. Two actuators 315 such as hydraulic cylinders (only one shown) are used to cause the rotation of the blade about the vertical axis defined by vertical pivot location 311. These actuators are also pivotally coupled directly to the blade 300 at attachment points 312 (only one shown). These points 312 are situated such that one is located to the left of the pivot location 311 and the other is located to the right of the pivot location 311. The attachment points 312 are preferably equally spaced from the pivot location 311.

Other implementations of lift assemblies for trip edge blades are well known to those skilled in the art, and are widely used. While these other implementations can differ in various respects, there are several common characteristics among them. First, the biasing elements 303 are located on the blade 300. Second, the cylinders 315 attach directly to the blade, since the blade 300 is unable to pivot about a horizontal axis. Third, the pivot point 311 about which the blade vertically rotates typically is integral with the blade, because of there is no need for the blade to freely pivot about a horizontal axis.

The differences enumerated above have led snow plow manufacturers to develop separate lift assemblies for each type of blade. The need for two lift assemblies is detrimental to manufacturers and dealers, who must forecast the demand of not only snow plow systems, but the percentage of each type. Similarly, more dissimilar parts need to be manufactured and inventoried because of this duality. Finally, there are more spare parts and replacement parts because of this situation. The present invention significantly reduces the number of different components required to implement both full moldboard trip blades and trip edge blades by using a common lift assembly for both systems. The lift assembly of the present invention is that which is used in the trip edge system of FIG. 3, although other lift assemblies are also possible.

FIG. 4 demonstrates the use of the lift assembly of FIG. 3 in conjunction with a full moldboard trip blade. Lift assembly 310 is pivotally coupled to bracket 410 at vertical pivot location 311, preferably through the use of a bolt or other suitable fastener. Actuators 315, such as hydraulic cylinders (only one is shown) are similarly pivotally coupled to bracket 410 at attachment points 412 (only one is shown) in a similar manner. Bracket 410 is thereby able to pivot about the vertical pivot location 311 in response to relative movement of the actuators 315. Bracket 410 is also unable to rotate in the horizontal axis due to its coupling to lift assembly 310. Full moldboard trip blade 420 is pivotally attached to bracket 410 at attachment points 413 (only one is shown), preferably by use of a bolt, pin or other suitable fastener. This attachment allows blade 420 to rotate about the horizontal axis defined by attachment points 413. Finally, one or more biasing elements 425 are coupled to blade 420 on end 426, and are coupled to attachment points 414 (only two are shown) on bracket 410. As before, tension from these biasing elements 425 maintains the blade 420 in its operative position.

Thus, the attachment points on bracket 410 are used to create two axes about which there is rotation. The attachment at vertical pivot location 311 allows the bracket to rotate about a vertical axis defined by that point. Similarly, the attachment points 413 allow the blade 420 to rotate about a horizontal axis defined by these attachment points.

Through the addition of bracket 410, it is therefore possible to employ the same lift assembly 310 for both trip edge blades and full moldboard trip blades. This allows manufacturer and dealers to manufacture and stock a single lift assembly, suitable for use with both systems.

While a specific lift assembly is illustrated in the figures, the invention is not limited to only that assembly. The present invention is suited for any lift assembly which comprises a vertical pivot location and two actuators used to rotate the blade about that pivot location.

FIG. 5 illustrates the preferred embodiment of the bracket 410. In the preferred embodiment, the bracket 410 comprises an upper, arcuate bar 500 and a lower elongated bar 510. These bars, preferably tubular members constructed of steel, are affixed to each other at or near both ends, preferably by welding. The bars are also connected via one or preferably more support bars 520, which extend downwardly from the upper bar 500 to the lower bar 510 and are affixed to the upper and lower bars, preferably by welding. Vertical pivot point 311 is preferably located in the center of the upper and lower bar, such that the bracket is symmetrical about the vertical pivot location 311. Attachment points 412, which are preferably holes into which bolts, pins or other fasteners are inserted, are formed in right angle members 418 affixed to the elongated bar 510 and respective supports bars 520 as shown. The actuators are affixed thereto by inserting the fastener through each hole in the right angle members 418 and into the actuator, as shown in FIG. 4. Attachment points 414 are preferably holes into which the ends of the biasing elements, preferably springs, are affixed. Similarly, attachment points 413 (FIG. 4) are preferably holes through which bolts, pins or other fasteners are inserted to affix the plow blade. 

1. An adapter adapted to be interposed between a snow plow lift assembly adapted to couple directly to a trip edge snow plow blade having a first central pivot location and second and third pivot locations, wherein said lift assembly comprises a vertical pivot location and two actuators, and said coupling comprises a first fastener adapted to pivotally affix said vertical pivot location to said first central pivot location and two second fasteners adapted to pivotally affix said two actuators to respective ones of said second and third pivot locations, and a moldboard trip snow plow assembly, wherein said moldboard trip snow plow assembly comprises a moldboard blade having two horizontal pivot locations and at least one biasing element, said adapter comprising: a first attachment point adapted to be pivotally affixed to said vertical pivot location on said lift assembly; second and third attachment points adapted to be pivotally affixed to respective ones of said two actuators; fourth and fifth attachment points adapted to be pivotally affixed to respective ones of said horizontal pivot locations on said moldboard snow plow blade; and at least one sixth attachment point adapted to be affixed to a respective one of said at least one biasing elements.
 2. The adapter of claim 1, wherein said actuators comprise hydraulic cylinders.
 3. The adapter of claim 1, wherein said biasing element comprises a compression spring.
 4. A method of attaching a snow plow lift assembly having a vertical pivot location and two actuators to a moldboard snow plow blade assembly comprising a moldboard blade having two horizontal pivot locations and at least one biasing element affixed to said moldboard, said method comprising: providing a bracket, said bracket comprising a first attachment point adapted to be pivotally affixed to said vertical pivot location on said lift assembly; second and third attachment points adapted to be pivotally affixed to respective ones of said two actuators; fourth and fifth attachment points adapted to be pivotally affixed to respective ones of said horizontal pivot locations on said moldboard snow plow blade; and at least one sixth attachment point adapted to be affixed to a respective one of said at least one biasing element; pivotally affixing said vertical pivot location to said first attachment point; pivotally affixing said two actuators to said second and third attachment points; pivotally affixing said horizontal pivot locations to said fourth and fifth attachment points; and affixing each of said at least one biasing elements to a respective one of said at least one sixth attachment points.
 5. A collection of parts adapted to be used to create a trip edge snow plow system or a moldboard snow plow system, comprising: a snow plow lift assembly, said lift assembly having a vertical pivot location and two actuators; a trip edge blade assembly, having a central pivot location and second and third pivot locations, wherein said central pivot location is adapted to be pivotally affixed to said vertical pivot location and said second and third pivot locations are adapted to be pivotally affixed to respective ones of said actuators; a moldboard blade assembly, comprising a moldboard blade having two horizontal pivot locations and at least one biasing element affixed to said moldboard blade; and a bracket comprising a first attachment point adapted to be pivotally affixed to said vertical pivot location on said lift assembly; second and third attachment points adapted to be pivotally affixed to respective ones of said two respective actuators; fourth and fifth attachment points adapted to be pivotally affixed to respective ones of said horizontal pivot locations on said moldboard snow plow blade; and at least one sixth attachment point adapted to be affixed to a respective one of said at least one biasing element, wherein said trip edge snow plow system comprises said lift assembly and said trip edge blade assembly, and said moldboard snow plow system comprises said lift assembly, said bracket, and said moldboard blade assembly.
 6. A mounting adapter for allowing a plurality of identical lift assemblies to be each mounted to one of a plurality of different snowplow blades selected from the group consisting of trip edge blades and blades devoid of a trip edge, said adapter comprising: a first attachment point adapted to be pivotally coupled to said lift assembly to define a vertical axis about which said blade devoid of a trip edge is adapted to move; second and third attachment points adapted to be pivotally coupled to said lift assembly to allow movement of said blade devoid of a trip edge about said vertical axis; fourth and fifth attachment points adapted to be pivotally coupled to said blade devoid of a trip edge to allow movement of said blade devoid of a trip edge about a horizontal axis.
 7. The mounting adapter of claim 6, wherein said blade devoid of a trip edge further comprises at least one biasing element, and wherein said adapter comprises one or more biasing element attachment points each adapted to be coupled to a respective one of said one or more biasing elements. 